Some known improvised explosive device (IED) threats and newly emerging IED threats use steel-cased devices containing thermal and/or impact sensitive propellants or thermal or impact sensitive explosives. Currently used render safe procedures (RSPs) carried out with gun-type EOD disruptors use high velocity steel or other metal or metal composite projectiles moving in excess of 2000 fps to vent hard cased IEDs. The unexpected consequences of this approach are the tremendous pressures and shock waves that are produced. For example, steel projectiles that hit steel targets have matched shock impedances and thus efficiently propagate shock waves. Such shock waves can compress the explosives that fill the IED. The explosives are pressed against the side of the casing in the projectile impact zone.
The explosives' compression occurs quickly and adiabatic conditions are created. For example, after projectile impact, black powder inside an IED can be compressed and heated to ignition, resulting in an IED exploding and fragmenting. In the case of double and triple-based smokeless powder, the nitroglycerin-containing propellant detonates immediately after the projectile hits the IED. The RSP creates an explosion that is far more violent and lethal than if the IED simply functioned as designed. Most IEDs are initiated through pyrotechnic fuzes or electric matches. Of particular concern are steel capped pipe bombs, steel plugged elbow pipe bombs, and improvised grenades.
A conventional technology may pierce relatively thin-walled steel containers, for example, a steel drum or a steel ammo box, without initiating the explosive therein. Even so, such conventional technology cannot pierce, for example, 2 inch diameter schedule 40 steel cased pipe bombs. A need exists for EOD projectiles that can penetrate a relatively thick steel case of an explosive device without detonating the explosives in the device.